Generally, a plastic bottle, such as a PET bottle, is widely known as a beverage container. Plastic bottles vary in their sizes. Bottles may have a small size, which is less than 500 ml, a medium size, which is around 1,000 ml, and a large size, which is about 1,500-2,000 ml.
In order to store plastic bottles of various sizes, a refrigerator typically has a bottle holder or pocket that can accommodate large bottles. A small refrigerator, however, may not be equipped with a bottle holder or pocket for large or even medium-size bottles, and those bottles can only be stored on the side on shelves. Even for a large refrigerator, if the bottle holder or pocket is occupied by other items, bottles may have to be stored on the shelves.
Recently, a bottle having a distinctive cross-sectional shape has been desired to attract many consumers at shops. For example, bottles having a circular, rectangular, or heart-shaped cross-section or bottles having a flat cross-sectional shape, as a whole, have been developed. (See Japanese Laid-Open Patents H11-91754, H7-300121, 2006-16076, and 2005-247393).
A cross-sectional shape of a bottle is designed in consideration for pressure in the bottle after it is filled with a liquid. In general, many bottles for soft drinks, such as juice or tea, have a rectangular cross-section. In addition, these bottles are often provided with ribs or grooves to prevent deformation of the bottles due to pressure decrease after they are filled with a liquid and a loss of commercial value. On the other hand, bottles for carbonated drinks typically have a circular cross-section. This is because the bottles need to be able to withstand positive internal pressure to which they are exposed.
Rectangular cross-sectional bottles may be stably placed and stored in a refrigerator. The rectangular cross-sectional bottles, however, have low resistance against positive internal pressure caused by carbonated drinks and are not suitable for storing carbonated drinks. On the other hand, while circular cross-sectional bottles may be able to withstand positive internal pressure, they roll easily on a refrigerator shelve. Furthermore, shortening the height of the circular cross-sectional bottles often results in an increase in diameter, and it becomes difficult to store them in a bottle holder or pocket in the refrigerator.